Thread-micrometer.



J. T. SLOCOMB.

THREAD MICROMETER.

APPLICATION man JUNEH. 19 l7.

1,291,21 1., Patented Jan. 14,1919.

I mmw JOHN '1. SLOCOMB, 0F PROVIDENCE, EHOIDE ISLAND, AEBIGrhlUT-t TUll. T. SLOCOMB CUMPANY, OF PROVIDENCE, RHOIDE ISLAND, 1-1 CORPORATION OFRHODE ISLAND.

THREAD-LWIIGROIVIETEE.

Application filed June 11, 1917.

To aZZ whom it may concern:

Be it known that T, JOHN-T. SLoooMB, a citizen of the .United States,residing at Providence, in the county of Providence and State of RhodeIsland, have invented certain new and useful Improvements inThread-Micrometers, and T do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

The present invention relates to micrometers, and more particularly tomicrometers for measuring. the diameter of threaded work. 1 it Theobject of the present invention is to devise a micrometer for makingaccurate measurements of threaded work throughout a wide range both asto diameter and size of thread. A further object of the presentinvention is to improve the accuracy of thread micrometers by providinga thread-engaging anvil which has a limited rotational movement toadjust itself accurately upon the work. 7

With these and other objects in view, as will hereinafter appear, thepresent invention consists of the micrometerhereinafter described andmore particularly defined in the claims.

In the accompanying drawings which illustrate what is now considered apreferred form of the present invention, Figure 1 is a side elevation ofthe micrometer; Fig. 2 is a cross section on line 2-2, Fig.1, looking inthe direction of the arrows, and Figs. 3 and f are views of the anvilmembers detached showing their difierent lengths of stem and sizes ofanvil for use upon difi'erent diameters of work and sizes of thread.

As shown in Figure 1 the micrometer comprises a substantially til-shapedframe 5having at one end a cylindrical boss 6 in which is rotatablymounted the threadedmicrometer spindle 7 having the tapered threadengaging face 8 and the usualgraduated thimble 9. v v I The opposite endof the frame is provided with a pair of cylindrical bosses 11 and 12 inaxial alinement with each other and with the micrometer spindle 7. Theboss 11 is provided with a cylindrical recess in which is mounted theanvil member 13 carrying a thread engaging anvil 14 on its end towardthe micrometer spindle. This anvil, as well Specification of LettersPatent.

Patented Jan. 14f, rare.

Serial No. 173,9641.

shown in Fig. 1, which illustrates the memfrom time to time, as may benecessary to give true readings of the micrometer, the

frame being split as shown in Fig. 2, and a clamping screw 19 beingprovided for pinching the frame upon the abutment screw 18. The anvilmember 13 may be clamped in fixed position in the boss 11 when theoperator so desires by means of the clamping screw 21 and nut 22 havingthe handle 28.

In order to permit the anvil member13 to have a limited amount ofrotation to adjust itself upon the work, and also to prevent the anvilmember from accidental displacement a split collar 25 has been providedwhich may be secured by means of the clamping screw 26 upon the end ofthe member 13 which projects from the boss 11 toward the abutment screw18. This collar is provided with a flat face 27 (see Fig. 2) betweenwhich and the frame at 28 there is a sufficient clearance to permit aslightrotational movement of the anvil so that it may, adjust itselfupon the thread of the work, the nut 22 being at such times loosenedupon the clamping screw 21 by. means of the handle 23.

When the anvil member shown in full lines in Fig. 1 is used, themicrometer is adapted to measure work only slightly less in diameterthan the distance shown between the anvil 14: and thecontact face 8 ofthe spindle. In order to permit work of much smaller diameter to bemeasured, the anvil member 30 shown in Fig. 3 will be substituted,bringing the anvil then into the po sition shown in dotted outline inFig. 1. Where the micrometer spindle is graduated infractions of aninchand has a range of movement of one inch, the anvil members willdifier in length by one inch so that the workman may obtain the truedimension of the work by simply adding to the readings of the micrometerspindle the number of inches required for each. particular anvil.

"theclampin'gnut 22 is loosened, and the an- Vll memberis inserted inthe recess in the "boss 11, the :end of the member passing through'thecollar 25 and into engagement with the adjusting screw 18. The anvilmember is then turned to bring the notch into substantial alinement withthe plane of the frame, and the clamping screw 26 is tightened While"the anvil member is held in this position. The'correctness of theadjustment'oftheabutment screw 18 may be "tested by means of a standardwhich is placed "between the anvil and the contact face 8 on themicrometer spindle. If the mici'ometefdoesnot give the exactpredet'ermined reading with this standard, the screw 19 will be'loosenedand the abutment "strewn; adjusteduntilthe proper readingis'sciii'ed, when the clamping screw 19 is to prevent change in theadjustment.

, The micrometer will-be used in the ordinary manner,'-the notch in theanvil engaging fa thread -and the micrometer spindle being "turnedtobringthe-contact'face 8' on the inclined face of two adjacent threadswith the proper'amount of pressure. Preferably 'theclampin g nut 22will'be loose so that the an'vil "m'ay rotate slightly to adjust itselfupon the work. The reading of the micrometer will then give the truediameter of the threaded "work.

While thedrawin'gs illustrate, and I have "described what is nowbelieved to be the preferred embodiment of the present in- "vention,it"is "tobe understood that it may be embodied in various other formsand arrangements within the limitations defined in the claims.

H'avingthus-described the present invention, "what 'is cl'aimed is 1. Ina micrometer, the combination with theframe provided with two axiallyalined :r'eces'ses, 'ofthe'mi'crometer spindle rotatably A mountedfin'onefof said recesses, an anvil member mounted for free rotationwithout axial movement in the other recess and provided "with"an'anv1lhav1n'g a work enga'ging notch opposite the end of the mi-'crometerspindle, and means for limiting the extent of rotationalmovement of the member and anvil whereby the anvil will be held inposition to engage the work and to adjust itself thereon.

2. In a micrometer, the combination with the frame, of the micrometerspindle rotatably mounted therein, and a plurality of interchangeableanvil carrying members adapted to be mounted in the frame and providedwith thread-engaging anvils each having a thread-engaging notch, thesize of the notch varying in the different anvils to fit difierent sizesof thread, and the anvil members being of different eli'ective lengths,the longer members having the smaller notches.

3. In a micrometer, the combination with the frame provided with aplurality of recesses, a. micrometer spindle rotatably mounted in one ofsaid recesses, an anvil member mounted for rotation without axialmovement in another of said recesses and in axial alinement with'thespindle and provided with an anvil and having a notch on its workengaging face, and a collar detachably mounted upon said member andarranged to engage the frame to limit the extent of rotational movementof the member whereby the anvil is held in position to engage the workand adjust itself thereon.

4. In a micrometer, the combination with a substantially U-shaped frameprovided at one end with a pair of axially alined cylindrical bosses, ananvil member rotatably mounted in one of said bosses, an adjustableabutment screw mounted in the otherboss and engaging the end of themember, a collar secured to saidmember between the two bosses to limitthe extent of rotational movement of the member, and a micrometerspindle mounted in the other end of the frame.

' 5. In a micrometer, the combination with the frame, of the micrometerspindle rotatably mounted therein, an anvil member mounted in the framefor rotation without axial movement and provided with a work engagingface shaped to fit the threads of the work, and'devices for holding themember from rotation and for permitting rotational movement in eitherdirection and only to a limited extent, whereby the face of the anvilmember will be held in position to engage the threads of the work and toadjust itself thereon, said devices being under the control of theoperator.

JOHN T. SLOCOMB. 'Witnesses:

HOWELL C. SHORT, LILLIAN E. WHITTAKER.

initia or thismatentmay be obtained for five cents each, by addressingthe "Commissioner of intents, Washington, D. G.

